Optimization of Neem Seed Oil Extraction Process Using Response Surface Methodology

Abstract

A central composite design (CCD) consisting three factors (solvent composition, temperature and time of extraction) at five levels was used to study the solvent extraction of neem oil from its seed using n- hexane and ethanol. Neem oil yield_, pH, refractive index, acid value, iodine value and saponification value were evaluated as the responses. Forty-two experimental runs resulted from the CCD with a minimum oil yield of 12% and maximum of 41%. Response surface methodology was used to analyse the results of the CCD of the extraction processes. The optimum values for yield_, pH, refractive index, acid value, iodine value and saponification value from the surface plot was 43.48%, 4.99, 1.56, 1.411g/g, 89.35g/g, and 176.64 mg/g respectively.   The maximum predicted percentage yield was 43.48% at solvent composition of 80.77% n hexane, 34.93°C and 6 hours duration of extraction. The five validation experiments had optimum oil yield range between 32.85% and 37.20% while their accompany quality characteristics were not significantly different from the simulated values at p<0.05

Key words: Neem Oil, Response Surface Methodology, Central Composite Design